Taking this trait lowers the Courier's base Perception by 1 point when attempting to qualify for perks. This means the player character must have a base Perception of 7 to qualify for all Perception-based perks (except Infiltrator and Hobbler which require 8 instead of the usual 7 due to the -1). This can be achieved by raising Perception to 7 at creation, or Perception 6 with Intense Training added later to boost it to 7.

Wearing glasses with this trait will actually raise Perception by +2 as seen in the Pip-Boy display, thereby nullifying the -1 penalty in terms of compass and skill benefits (though not the damage to base Perception, thus requiring the player having 1 more point of permanent Perception to take an associated perk). Perception 7 at creation, with this trait (glasses equipped), Intense Training +1 or an implant and a +1 Perception headgear will still total 10 Perception.

If the Courier's Perception is to 1 or 10 at character creation, they cannot take this trait.

While most types of glasses grant +2 to Perception with this trait, the Lucky shades grant +3. Without this trait, the Lucky Shades do not grant any extra Perception.

Biker goggles are not affected by this trait, even though they have attachments that appear to have glasses and lenses which cover the player character's eyes. However, biker goggles are only intended to protect the eyes from wind, dust and other flying particles encountered commonly while riding motorcycles: things not directly related to the functionality of the eyes.